24 + 1 Toothed Wheel (Toyota ESA) inside the distributor using either 2 or 3 VR sensors (Ne, G1 and G2), depending on model. With the 3 VR sensor distributor we are only concerned with 2 of the sensors, one which reads the 24 teeth and one which picks up a single pulse per revolution. On 4 cylinder engines the third sensor (G2), which also picks up on the single tooth, will be redundant. This might help you out